Sorry it's taken a while to get back, I got tied up with a bunch of stuff.
I contacted Hiren's website as well to see if I can get any input from them. I would still like to get Hiren to work, I'm finding more and more it would be useful for me.
I have an older laptop running a BIOS system, and I was actually able to get the Hiren's PE to load up through USB on it, so the image and thumbdrive work.
When I tried again on my current system I noticed there are 2 options to boot from the thumbdrive, UEFI & USB.
When I try the UEFI that's when it get's stuck on the Asrock logo.
When I try the USB option I will get the Windows logo, but it won't go any further. There's no circular loading logo.
How does Windows PE work? Does it use the local drive for temp files, or does it keep everything on the thumbdrive, or does it keep everything in RAM? I don't know if it makes a difference, but the system drive on my computer is formated with MBR.
Not sure what you are suggesting with RMPrepUSB, is it a Rufus equivalent?